When discussing the “power” of computers, people typically focus on speed—so-called processing power. The electrical power consumed by the computers gets less attention. But to people who operator computer data centers—facilities that contain hundreds or thousands (or tens of thousands) of computers serving requests from remote users—the electrical power can be every bit as important as the processing power. Each computer can consume several hundred watts—the same as several floodlights. Multiplying that total across thousands of computers should make plain that the potential consumption level can be fairly high.
The operating computers convert all of that consumed electricity into heat. And that heat has to be removed. So operating a data center is like an electrical double whammy—you have to pay once to use the electricity, and you have to pay again to remove the effects of the use of the electricity (which itself requires more electricity). The effects of power consumed by the critical load in the data center are thus compounded when one incorporates all of the ancillary equipment required to support the critical load, such as pumps, chillers, and other such components.